Interior design help for everyone.
There are an amazing amount of beautiful range hoods available now. Glass, steel and custom wood are all options. But, you need to know the SIZE of range hood you need, not necessarily the dimensions (for this topic), but the amount of CFM (cubic feet per minute) needed for your hood. Here's the rule of thumb, remember to double check with your contractor and local building code. First you need to select your stove, or cook top. Then you need 100 CFM for every 12" of stove width. For example a 30" stove (2.5') x 100 CFM= Approx. 250 CFM needed, as a minimum. But we can't just stop there... We need to keep the room size in mind. Larger rooms need more CFM to clear the cooking odors away. A range hood should exchange the air in the kitchen 15 x per hour. Here's a helpful example. If your kitchen is 12' x 15' and 10' high, that equals 1,800 cubic feet. To find the size of fan needed, multiply the cubic feet x the # of air exchanges (15) then divide by 60 (minutes in an hour). In our example that would be: 1,800 x 15 = 27,000 divided by 60 = 450. You need 450 CFM minimum for this size of kitchen. Are we finished? Not yet. Gas ranges deliver a lot more heat than electric ranges. So we need to take this into consideration. Most gas burners put out approx. 10,000 BTUs per burner. Multiply that by the number of burners, 5 shown here = 50,000 BTU Then divide by 100 to find the minimum CFMs needed. In this case 500 CFM. Now we still aren't quite finished. What about the size of the duct work, number of turns, etc.? Most HVAC suppliers recommend smooth 8" metal pipe. Add 1 CFM per foot of pipe and add 25 CFM for each bend and 40 CFM for the roof cap. Let's estimate this example as being 100 CFM needed. Now, we ARE finished. Take the rating for the stove width (250 CFM in our example), room size (450 CFM minimum), burner type (500 CFM minimum). The highest number is 500, then add your ductwork CFM calculations (100) and you would need a total of 600 CFM for this range size, kitchen size, range burner and ductwork. Please remember to double check if you need a licensed mechanical contractor to install a make up damper to switch on simultaneously with the kitchen range hood to bring in fresh air to prevent a negative pressure in the home. There are many varying factors at play - location of your home, gas or electric range, differing building codes, etc. In BC, Canada our municipality states: makeup air is only required if the displacement of air exceeds .5 air changes per hour and is used with a fueled appliance (i.e. gas stove). I hope this helps. Be sure to always discuss this with your contractor HVAC installers and appliance providers. Check out our 15 Steps to designing your Dream Home below. Also you might like our popular post on: Recessed Lighting Spacing: How many recessed lights do I need? How far apart do I place my lights? Click below to read the article Any other Design questions, just let me know, we offer Paint selection advice, one room Interior Design and Whole Home Interior Design Thanks for stopping in! Virtual Interior design help throughout Canada and USA
38 Comments
Andrew Radetich
12/17/2016 12:53:14 pm
In an open floor plan where the kitchen is open to the adjacent dining room and living room spaces, are those adjacent spaces apart of the room area (cu ft) that is used to determine range hood CFM?
Reply
mia
11/10/2019 10:38:31 pm
thanks
Reply
Abdul Rahman bin Hashim
10/6/2020 08:43:38 pm
Thank you Jil for your advise on kitchen hood design 1/18/2018 08:47:03 pm
Hi Andrew,
Reply
Minhaj
10/27/2018 02:14:08 am
Hello,
Reply
10/28/2018 07:36:57 pm
Hi Minhaj,
Reply
Jason
11/9/2018 10:57:11 pm
Is this accurate? I’m just wondering because according to my HVAC tech, anything more than 300 cfm range hood would require a make up air system as this causes some back drafting and depressurization which is dangerous and make up air system is very costly.
Reply
11/10/2018 11:47:57 am
Hi Jason,
Reply
11/15/2018 12:47:12 pm
Jill,
Reply
JIL SONIA INTERIORS
11/16/2018 12:24:30 pm
Hi Charles,
abhilash
1/21/2019 05:15:56 am
HOW TO CALCULATE KITCHEN EXTRACT CFM??DO YOU HAVE ANY FORMULA.PLEASE EXPLAIN
Reply
JIL SONIA INTERIORS
1/21/2019 09:49:46 am
Hi Abhilash,
Reply
Stephen Gatz
2/4/2019 02:43:37 pm
Where did you get the sizing information from?
Reply
JIL SONIA INTERIORS
2/4/2019 03:28:42 pm
Hi Stephen .Thank you for your comment. I appreciate it. I received this information from our BC building code and confirmed it by calling them.
Reply
6/17/2019 09:12:09 am
Hey Jil,
Reply
6/17/2019 12:00:24 pm
Hi John,
Reply
10/17/2019 04:29:30 am
great info now i wonder about at what point should i temper the make up air for the kitchen exhaust fan.
Reply
10/17/2019 10:30:58 am
Hi Jeffrey,
Reply
3/23/2020 09:22:56 am
Oh thank you so much for commenting, I'm glad you found it helpful. I try and write in an easy to understand way.
Reply
mark chase
4/24/2020 02:34:38 pm
Hello, I am having trouble finding a 36" 450CFM under cabinet range hood. I have found ones at slightly less around 430CFM.
Reply
4/24/2020 04:05:03 pm
Hi, thanks for commenting!
Reply
Patrick villa
6/17/2020 07:30:21 am
I want to remove the vent hood in my house and put in a surface mounted vent system bc I can’t see my kitchen cabinets. I'm having trouble figuring out which system I need bc the room is 23’x17.5’x11.9’ high. I also have two openings or open door casings and I’m at a lose bc no one will help me? Can you please help?
Reply
6/17/2020 11:16:04 am
Hi Patrick,
Reply
11/18/2020 10:23:11 am
Oh that sounds heavenly Samantha, I don't think I've smelled Madrone wood before!
Reply
4/17/2021 02:54:57 am
Wonderful information about designblog, thanks a lot for sharing kind of content with us. Your blog gives the best and the most interesting information. I wonder if we can gather such practical information about it, a great post definitely to come across.
Reply
4/19/2021 12:20:38 pm
Oh thank you so very much for your kind comments.
Reply
12/17/2021 11:37:09 am
Hi Riya,
Reply
1/17/2022 11:18:22 am
Thanks so much for taking the time to comment, I'm glad you enjoyed it!
Reply
Abdul Rahman
2/4/2022 12:36:21 am
Please share industrial kitchen exhaust cfm to air conditioning cfm?
Reply
2/4/2022 01:15:58 pm
Hi Abdul,
Reply
3/23/2022 09:28:35 am
Hi Swati,
Reply
Your comment will be posted after it is approved.
Leave a Reply. |
Author:Jil Sonia McDonald - Interior Designer of Jil Sonia Interior Designs. Archives
April 2023
Categories:
All
Design Links Bloggers I follow:
Kimberley Seldon Design Linda Holt Interiors The Decorologist Warline painting Savour Partnership Ina Goetz Photography |